Introduction: Lymphatic abnormalities have being describred after functional singleventricle palliation using Magnetic Resonance (MR) lymphangiography. Pulmonary artery hypertension (PAH) may occurs in univentricular and biventricular circulation. PAH may increase systemic venous pressure impairing lymphatic drainage. The objective was to quantify thoracic duct diameter index (TDDI) in PAH patients.
Material and Methods: we retrospectively reviewed MR images T2 weighted limphangiography of 11 patients with PAH, age 14.7±8.6 years, between January 2017-October 2019, performed with 3T Siemmens MR, with respiratory navigator, without anesthesia/contrast enhancement. Patients where divided in 2 groups: 4 univentricular circulation (3 unfenestrated Fontan-Kreutzer, 1 Glenn), 7 biventricular circulation: 5 isolated PAH and 2 Eisenmenger síndrome (ES). PAH was defined on cardiac catheterization: univentricular circulation when transpulmonary gradient >6mmHg; biventricular circulation when mean pulmonary artery pressure >20mmHg,
pulmonary vascular resistance >3Woods Units m2. TDDI mm/m2 was measured proximal to left venous yugulosubclavia junction. Real-time assesment MR cineangiogram ejection fraction was measured in all patients.
Results: Univentricular circulation encluded 2 patients with protein loosing enteropathy and 1 with plastic bronchitis; TDDI 4.8±1.48mm/m2, transpulmonary gradient 7.75±1.5mmHg and ejection fraction 53±9%. Univentricular circulation TDDI when compared with isolated PAH and ES was significantly greater (p<0.001). Biventricular circulation encluded 3 idiopatic, 2 hereditary and 2 ES. TDDI 2.32±0.97mm/m2, mean pulmonary artery pressure 56.5±17.69mmHg, pulmonary vascular resistance 13.7±7.2WU/m2 and ejection fraction 55.8±8.3%. Isolated PAH TDDI 2.54±1.09mm/m2 vs ES 1.78±0.30mm/m2 (p:NS).
Conclusion: Lymphatic TDDI MR was significantly greater in univenticular circulation when compared with biventricular circulation PAH patients. Biventricular circulation PAH needs a greater number of patients and comparison with normal reference values in order to obtain statistical diferences. Lymphatic thoracic duct MR T2 weighted may be useful in PAH cardiovascular MR protocol in order to quantiphy another risk stratification factor.